Memory devices are used in storage elements for many products such as MP3 players, digital cameras, computer files, etc. As the application increases, the demand for the memory device focuses on small size and large memory capacity. For satisfying the requirement, a memory having a high element density is needed and a 3D stacked memory structure is developed.
In 3D memory, vertically stacking the periphery and memory elements can help to reduce the chip area and the overall cost. Generally, high thermal can help to improve the device performance/reliability of the array device. However, only periphery first process is used traditionally, such that no high thermal process is allowed during the manufacturing processes of the array device to avoid damage on periphery elements.